Answer
The solution set is {$-\frac{1}{2},0$}
Work Step by Step
$|x^2+3x|=|x^2-2x|$
$x^2+3x=x^2-2x$ or $x^2+3x=-1(x^2-2x)$
$x^2+3x-x^2+2x=0$ or $x^2+3x+x^2-2x=0$
$3x+2x=0$ or $2x^2+x=0$
$5x=0$ or $x(2x+1)=0$
$x=0$ or $x=0$ or $x=-\frac{1}{2}$
The solution set is {$-\frac{1}{2},0$}